Custom Cloud Console can be themed at the Account Governance and Control Account levels in WACM.
Once the theming and regions are configured, Channel Accounts will inherit these settings from the Control Account. Channel Accounts can further manage regions and members for each one of their sub-accounts by clicking into the desired sub-account and selecting the "Members" or "Regions" tab.
Read more about Custom Cloud Console here.
For more information about Channel Accounts check out the article: What is Wasabi Account Control Manager's Channel Account feature?